The present invention relates to a process for producing aminooxyacetic acid salts which are useful as intermediates for the production of pharmaceuticals, agrichemicals and other chemicals.
While several methods are known in the art of producing aminooxyacetic acid, the following are representative: (1) aldoxime or ketoxime is reacted with a halogenoacetic acid and the resulting oxime-O-acetic acid is either hydrolyzed with an acid or reacted with hydrazine to obtain aminooxyacetic acid [Org. Syn. Coll., vol. 3,172 (1955); and Atti. soc. peloritana sci. fis. mat. e net, 4, 147 (1957)]; (2) an acid anhydride is reacted with hydroxylamine to obtain N-hydroxyimide, which is reacted with a halogenoacetic acid, and hydrazine is allowed to act on the reaction product to obtain aminooxyacetic acid [Bull. Soc. Chim. Fr., 833 (1976)]; (3) tert-butyl N-hydroxycarbamate is reacted with a halogenoacetic acid to obtain oxime-0-acetic acid, which then is decomposed with an acid to obtain aminooxyacetic acid (British Patent No. 1,394,170); (4) benzhydroxamic acid is reacted with an ester of a halogenoacetic acid to form a benzamidooxyacetic acid ester, which is hydrolyzed with an acid to obtain aminooxyacetic acid [J. Biochem. Japan, 23, 181 (1936)]; and (5) benzhydroxamic acid is reacted with .alpha.-halogenoacetic acid in absolute ethanol in the presence of metallic sodium and the reaction product is hydrolyzed in a solution of hydrochloric acid and glacial acetic acid to obtain aminooxyacetic acid (Unexamined published Japanese Patent Application No. 56-43245).
These conventional methods are defective in one way or another in that they attain only low yields or involve complicated reaction procedures such that the reactions are conducted under anhydrous conditions. Furthermore, these methods are not suitable for application to industrial operations since they employ expensive bromoacetic acid or reagents, such as phenylhydrazine or metallic sodium, which requires great care to avoid potential danger.
The present inventors, therefore, conducted intensive studies in order to eliminate these defects of the prior art and to establish an industrially feasible process for producing aminooxyacetic acid. As a result, the present inventors found that when a halogenoacetic acid, instead of an easter thereof, was reacted with benzhydroxamic acid in the presence of a metal hydroxide or a metal carbonate, benzoamidooxyacetic acid could be obtained in high yield while requiring simple reaction procedures. The present invention has been accomplished on the basis of this finding.